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Trematode Families
Trematoda is a class of flatworms known as flukes. They are obligate internal parasites with a complex life cycle requiring at least two hosts. The intermediate host, in which asexual reproduction occurs, is usually a snail. The definitive host, where the flukes sexually reproduce, is a vertebrate. Infection by trematodes can cause disease in all five traditional vertebrate classes: mammals, birds, amphibians, reptiles, and fish. Etymology Trematodes are commonly referred to as flukes. This term can be traced back to the Old English name for flounder, and refers to the flattened, rhomboidal shape of the organisms. Taxonomy There are 18,000 to 24,000 known species of trematodes, divided into two subclasses — the Aspidogastrea and the Digenea. Aspidogastrea is the smaller subclass, comprising 61 species. These flukes mainly infect bivalves and bony fishes.https://www.biotaxa.org/Zootaxa/article/view/zootaxa.3918.3.2 Digenea — which comprise the majority of trematodes — are f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lancetfish
Lancetfishes are large oceanic predatory fishes in the genus ''Alepisaurus'' ("scaleless lizard") in the monogeneric family Alepisauridae. Lancetfishes grow up to in length. Very little is known about their biology, though they are widely distributed in all oceans, except the polar seas. Specimens have been recorded as far north as Greenland. They are often caught as bycatch by vessels long-lining for tuna. The generic name is from Greek ''a-'' meaning "without", ' meaning "scale", and ''sauros'' meaning "lizard". Species The two currently recognized extant species in this genus are: * ''Alepisaurus brevirostris'' Gibbs, 1960 (short-snouted lancetfish) * '' Alepisaurus ferox'' R. T. Lowe, 1833 (long-snouted lancetfish) The anatomic difference between the two species is the shape of the snout, which is long and pointed in ''A. ferox'', and slightly shorter in ''A. brevirostris''. The long-snouted lancefish is found in the tropical and northern sub-tropical waters of the Pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osteichthyes
Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilage. The vast majority of fish are members of Osteichthyes, which is an extremely diverse and abundant group consisting of 45 orders, and over 435 families and 28,000 species. It is the largest class of vertebrates in existence today. The group Osteichthyes is divided into the ray-finned fish (Actinopterygii) and lobe-finned fish (Sarcopterygii). The oldest known fossils of bony fish are about 425 million years old, which are also transitional fossils, showing a tooth pattern that is in between the tooth rows of sharks and bony fishes. Osteichthyes can be compared to Euteleostomi. In paleontology the terms are synonymous. In ichthyology the difference is that Euteleostomi presents a cladistic view which includes the terrestrial tetrap ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cercaria
A cercaria (plural cercariae) is the larval form of the trematode class of parasites. It develops within the germinal cells of the sporocyst or redia. A cercaria has a tapering head with large penetration glands. It may or may not have a long swimming "tail", depending on the species. The motile cercaria finds and settles in a host where it will become either an adult, or a mesocercaria, or a metacercaria, according to species. Rotifers (''Rotaria Rotaria is a genus of asexual, microscopic animal known as a bdelloid rotifer. Analysis published in 2007 of morphology and DNA sequence data of species form the genus confirmed that despite their asexual mechanism of reproduction, two fundame ... rotatoria'') produce a chemical, Schistosome Paralysis Factor, suppressing cercaria swimming and reducing infections.{{cite journal , editor1-last=Khosla , editor1-first=Chaitan , last1=Gao, first1=Jiarong, last2=Yang, first2=Ning, last3=Lewis, first3=Fred A., last4=Yau, first4=Peter, la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Mekongi
''Schistosoma mekongi'' is a species of trematodes, also known as flukes. It is one of the five major schistosomes that account for all human infections, the other four being ''S. haematobium'', ''S. mansoni, S. japonicum, and S. intercalatum''. This trematode causes schistosomiasis in humans. Freshwater snail ''Neotricula aperta'' serves as an intermediate host for ''Schistosoma mekongi''. History Schistosomiasis was first reported in the Mekong River's Lower Basin region in 1957, from Laotian island of Khong to Cambodian province of Kratié, specifically. It was believed that the cause of these cases was ''Schistosoma japonicum'' until 1978, when ''Neotricula aperta'' was discovered and it was determined that the Schistosome was a unique species, ''Schistosoma mekongi''. In 1967, a WHO-mission was sent to Champasack, confirming the infections, and putting focus on how it was being transferred. In 1989, the Ministry of Health in Laos initiated its first medicational inter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Mansoni
A paired couple of ''Schistosoma mansoni''. ''Schistosoma mansoni'' is a water-borne parasite of humans, and belongs to the group of blood flukes (''Schistosoma''). The adult lives in the blood vessels ( mesenteric veins) near the human intestine. It causes intestinal schistosomiasis (similar to '' S. japonicum'', '' S. mekongi'', ''S. guineensis'', and '' S. intercalatum''). Clinical symptoms are caused by the eggs. As the leading cause of schistosomiasis in the world, it is the most prevalent parasite in humans. It is classified as a neglected tropical disease. As of 2021, the World Health Organization reports that 236.6 million people have schistosomiasis and most of it is due to ''S. mansoni''. It is found in Africa, the Middle East, the Caribbean, Brazil, Venezuela and Suriname. Unlike other flukes (trematodes) in which sexes are not separate ( monoecious), schistosomes are unique in that adults are divided into males and females, thus, gonochoric. However, a permanent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Malayensis
''Schistosoma malayensis'' is a schistosome parasite. It was first described in 1988 in Peninsular Malaysia and appears to be a zooenotic infection. The species is named after the country of Malaysia. The natural vertebrate host is van Müller's rat (''Rattus muelleri''). The intermediate hosts are aquatic snails, ''Robertsiella kaporenisis''. Among ''Robertsiella kaporenisis'' are two other ''Roberstiella'' species. Among humans exposed to this parasite the lifetime incidence appears to be 5–10%.Sagin D.D., Ismail G., Fui J.N., Jok J.J. (2001) ''Schistosomiasis malayensis''-like infection among the Penan and other interior tribes (Orang Ulu) in upper Rejang River Basin Sarawak Malaysia. Southeast Asian J. Trop. Med. Public Health 32(1):27–32 The symptoms are unclear, because the symptoms have never been reported. The disease has been little studied and it is currently considered to be a relatively minor public health problem. Taxonomy ''Schistosoma malayensis'' is a member ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Japonicum
''Schistosoma japonicum'' is an important parasite and one of the major infectious agents of schistosomiasis. This parasite has a very wide host range, infecting at least 31 species of wild mammals, including 9 carnivores, 16 rodents, one primate (human), two insectivores and three artiodactyls and therefore it can be considered a true zoonosis. Travelers should be well-aware of where this parasite might be a problem and how to prevent the infection. ''S. japonicum'' occurs in the Far East, such as China, the Philippines, Indonesia and Southeast Asia. Discovery ''Schistosoma japonicum'' was discovered in Kofu basin by Fujiro Katsurada, a pathologist in Okayama University in 1904. Later, Katsurada named the parasite ''Schistosoma japonicum''. Social impacts Individuals at risk to infection from ''S. japonicum'' are farmers who often wade in their irrigation water, fishermen who wade in streams and lakes, children who play in water, and people who wash clothes in streams. Importa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Intercalatum
''Schistosoma intercalatum'' is a parasitic worm found in parts of western and central Africa. There are two strains: the Lower Guinea strain and the Zaire strain. ''S. intercalatum'' is one of the major agents of the rectal form of schistosomiasis, also called bilharzia. It is a trematode, and being part of the genus ''Schistosoma'', it is commonly referred to as a blood-fluke since the adult resides in blood vessels. Humans are the definitive host and two species of freshwater snail make up the intermediate host, ''Bulinus forskalii'' for the Lower Guinea strain and ''Bulinus africanus'' for the Zaire strain.Tchuem Tchuenté LA, Southgate, VR, Jourdane J, Webster BL, Vercruysse J (2003) ''Schistosoma intercalatum'': an endangered species in Cameroon? ''Trends Parasitol'' 19: 141-153. Morphology The clinically defining characteristic of most schistosome species are their eggs' size and shape. The eggs of ''Schistosoma intercalatum'' have a terminal spine and tend to be moder ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosoma Haematobium
''Schistosoma haematobium'' (urinary blood fluke) is a species of digenetic trematode, belonging to a group (genus) of blood flukes (''Schistosoma''). It is found in Africa and the Middle East. It is the major agent of schistosomiasis, the most prevalent parasitic infection in humans. It is the only blood fluke that infects the urinary tract, causing urinary schistosomiasis, and is the leading cause of bladder cancer (only next to tobacco smoking). The diseases are caused by the eggs. Adults are found in the venous plexuses around the urinary bladder and the released eggs travels to the wall of the urine bladder causing haematuria and fibrosis of the bladder. The bladder becomes calcified, and there is increased pressure on ureters and kidneys otherwise known as hydronephrosis. Inflammation of the genitals due to ''S. haematobium'' may contribute to the propagation of HIV. ''S. haematobium'' was the first blood fluke discovered. Theodor Bilharz, a German surgeon working in Cair ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schistosomiasis
Schistosomiasis, also known as snail fever, bilharzia, and Katayama fever, is a disease caused by parasitic flatworms called schistosomes. The urinary tract or the intestines may be infected. Symptoms include abdominal pain, diarrhea, bloody stool, or blood in the urine. Those who have been infected for a long time may experience liver damage, kidney failure, infertility, or bladder cancer. In children, it may cause poor growth and learning difficulty. The disease is spread by contact with fresh water contaminated with the parasites. These parasites are released from infected freshwater snails. The disease is especially common among children in developing countries, as they are more likely to play in contaminated water. Other high-risk groups include farmers, fishermen, and people using unclean water during daily living. It belongs to the group of helminth infections. Diagnosis is by finding eggs of the parasite in a person's urine or stool. It can also be confirmed by fi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swimmer's Itch
Swimmer's itch, cercarial dermatitis or schistosome dermatitis is a short-term allergic contact dermatitis occurring in the skin of humans that have been infected by water-borne schistosomes, a type of flatworm. It is common in freshwater, brackish and marine habitats worldwide. The incidence of this condition may be increasing, although this may be attributed to better monitoring and reporting. Nevertheless, the condition is considered to be an emerging infectious disease. The main symptom is itchy papules (raised skin) that commonly occur within 2 days of infection. Initially, wheals develop quickly, then turn into maculae in about half an hour. Within 10–12 hours these turn into very itchy papules that reach their worst by the second or third day. The papules disappear in 1–2 weeks but secondary effects from scratching can continue longer. The intense itching, which peaks after 48–72 hours, is associated with pain and swelling of the affected areas. People repeatedly expo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trichobilharzia Regenti
''Trichobilharzia regenti'' is a neuropathogenic parasitic flatworm of birds which also causes cercarial dermatitis in humans. The species was originally described in 1998 in the Czech Republic and afterwards it was detected also in other European countries, e.g. Denmark, Germany, France, Iceland, Poland, Switzerland, or Russia, and even in Iran. For its unique neurotropic behaviour in vertebrate hosts, the host-parasite interactions are extensively studied in terms of molecular biology, biochemistry and immunology. Life cycle The life cycle of ''T. regenti'' is analogous to that of human schistosomes. Adult flukes mate in a nasal mucosa of anatid birds (e.g. ''Anas platyrhynchos, Spatula clypeata'' or ''Cairina moschata'') and produce eggs with miracidia which hatch directly in the host tissue and leak outside when the bird is drinking/feeding. Once in water, the miracidia swim using their cilia and actively search for a proper molluscan intermediate host (''Radix lagotis, Rad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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